Electromagnetic device.



W. C. NEAHR.

ELECTROMAGNETIC DEVICE.

APPLICATION FILED NOV. 14. I916.

Patented Sept. 25, 1917.

2 SHEETS-SHEET I.

i Mi! -Ew W. C. NEAHR.

ELECTROMAGNETIC DEVICE.

APPLICATION FILED N&V.14. I916.

Patented Sept. 25, 1917.

2 SHEETS-SHEET 2.

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UNITED STATES PATENT OFFICE.

WILL C. NEAI-IR, 0F DENVER, COLORADO, ASSIGNOR TO THE PROTECTIVE SIGNALMANUFACTURING COMPANY, OF DENVER, COLORADO, A CORPORATION OF COLORADO.

ELECTROMAGNETIL'! DEVICE.

Specification of Letters Patent.

Patented Sept. 25, 191 '7.

To all whom it may concern:

Be it known that I, WILL C. NEAHR, a citizen of the United States,residing at Denver, in the county of Denver and State of Colorado, haveinvented certain new and useful Improvements in Electromagnet Devices,of which the following is a specification.

The present invention relates to electromagnetic devices, and morespecifically to improvements in the mechanism disclosed in my co-pendingapplication, Serial No. 29,7 51.

The primary object is to provide a simple, compact, and thoroughlypractical structure which is of novel character, and which is not liableto derangement.

Another and important object is to provide mechanism peculiarly usefulin connection with alternating currents, and designed to preventexcessive chattering due to the frequency thereof while preventing themovable armature member from sticking after the current is cut off fromthe coil.

An embodiment of the invention that has proven entirely satisfactory, isillustrated in the accompanying drawings, wherein Figure 1 is a sideelevation of the device,

Fig. 2 is a top plan View thereof,

Fig. 3 is a vertical sectional view through the apparatus,

Fig. 4 is a horizontal sectional view,

Fig. 5 is a detail View in elevation of the switch mechanism andassociated parts, and

Fig. 6 is a reverse view of the parts illustrated in Fig. 5.

Similar reference numerals designate corresponding parts in all thefigures of the drawings.

Inthe embodiment illustrated, a casing is employed, preferablycomprising a cylindrical side wall 7 of glass mounted on a base 8, andhaving a cap 9 of insulating material. The base and cap are connected bytie bolts 10, which serve to hold the casing in assembled condition.

Within the casing, is suspended an electro-magnet 11 of suitableconstruction, preferably having a tubular core 12 that ties together alower head 13 and an upper head 14:, the coil 15 surrounding the coreand being suitably incased, as shown at 16. The head 14: is considerablyheavier than the head 13 and is provided with a pair of out standingears 17. Upright bolts 18 pass through the ears and through the cap 9,the heads 19 of the bolts being seated in grooves 20 formed in the undersides of the cars 17, and the stems of said bolts projected well abovethe cap 9, and being threaded, as illustrated at 21. Binding nuts 22 arescrewed upon the threaded ends, so that these bolts constitute bindingposts, as will be readily understood. The terminals 23 of theelectro-magnet are electrically connected to the bolts 18, so that saidbinding posts constitute means for attaching leads to theelectro-magnet. The head 1a of the electro-magnet is spaced aconsiderable dis tance from the cap 9 and for this purpose spacingsleeves 24: are located on the bolts 18 between the ears 17 and theunder side of the cap.

The space thus produced'between the head 1e and the cap 9 is utilized byan electric switch member. This member, as shown,

consists of spaced metallic fingers 25 piv-- oted, as shown at 26, toheads 27 formed upon the lower ends of binding posts 28 that extendthrough the cap 9 and project thereabove. These fingers 25 areelectrically connected to the heads 27 by suitable yielding strips 28The fingers 25 are furthermore connected by a cross bar 29 of insulatingmaterial, and said bar has an outstanding ear 30 through which is passedthe stem 31 of an armature 32 that is located in the tubular core 12 ofthe electro-magnet. This armature comprises a fixed upper member 33 ofmagnetic material through which the stem 31 slidably passes. Carried bythe lower end of the stem is a movable plunger element comprising asection 32 of magnetic material, the upper end of which is recessed andcooperates with the lower end of the fixed armature member 33. Thissection 32 is abutted against a shoulder 33 formed on the stem 31.Screwed upon the lower end of the said stem and therefore carriedthereby is a lower section 32 of magnetic material that is hollow toreduce its weight, and interposed between the sections 32 and 32 is asection 32 of non-magnetic material, preferably brass.

The section 32 is proportioned to the member 33, so that enough lines ofresidual magnetism are allowed to hold the weight of the lower memberduring the change of current, and while the voltage is at zero, but issmall enough so that the two will not stick when the circuit through thecoil has been broken. The concave upper end of the member 32" preventsany accumulation of dust and dirt on the top of the armature, whichmight cause the same to stick, and the small contact surface will holdbetter when the coil is energized, and will also break quicker after thecurrent has been cut o'd from the coil. By this arrangement therefore itis found that chattering is eliminated.

The upper end of. the stem 31 carries a flange 34k and a pad 35 whichare disposed below the car 30 of the cross bar 29, thereby constitutingan abutment that strikes the under side of said car, while a washer 36and clip 37 located on the stem above the ear 30 limits the downwardmovement of the stem and armature with respect to the bar.

Secured to the fingers 25 and extending above and below the free ends ofthe same, are contact members in the form of leaf springs 38 that havetheir free ends normally spaced from the free ends of the fingers.Arranged above the upper contact springs 38 are contact elements 39formed by the lower ends ofbinding posts 40, and other contact elements41 are located below the free ends of the lower springs 38, these lattercontact elements being carried by brackets 42 supported from the cap 9by binding posts 43.

With this arrangement, it will be evident that when the electro-magnetis deenergized, the armature 32 will drop, and as a consequence, theswitch member will fall, so that the lower contact springs 38 will enage the contact elements 41, and the free en s of the fingers 25 willrest upon the engaged tor-- minals of the springs 38, so as to insureand maintain an electrical contact. On the other hand, when theelectro-magnet is energized, the armature 32 will be elevated, therebyraising the switch member and causing the upper set of contact springs38 to engage the contact elements 39, the free ends of the fingers 25also engaging these contact springs and insuring a good electrical contact.

From the foregoing, it is thought that the construction, operation, andmany advantages of the herein described invention will be apparent tothose skilled in the art, without further description, and it will beunderstood that various changes in the size, shape, proportion and minordetails of construction may be resorted to without departing from thespirit or sacrificing any of the advantages of the invention.

Having thus fully described my invention, what I claim as new and desireto secure by Letters Patent, is:

1. In a device of the character set forth, the combination with a casinghaving a cap, of an electro-magnet having a head adjacent to but spacedfrom the cap, bolts passing through the head and cap for securing thetwo together, spacing sleeves loosely mounted on the bolts andinterposed between the head and cap, and leads for the magnet engagedwith the bolts and located on the underside of the cap.

2. In a device of the character set forth, the combination with a casinghaving a cap, of an electro-magnct having spaced heads, one of which isadjacent to but spaced from the cap, bolts passing through the heads andcap for securing the two together, means on the bolts interposed betweenthe head and cap, an armature receiving sleeve connecting the heads ofthe electro-mngnet, an armature movable in the sleeve, and a deviceactuated by the armature and located in the space between the head andcap.

3. In a device of the character set forth, the combination with spacedswinging arms pivotally mounted at one end and having their other endstree, of a member of insulating material connecting the arms betweentheir ends, spring contuct elements connected to the arms and extendingalongside the free ends thereof, contact elements with which the springelements coact, an electro-magnet and an armature operated by theelectro-magnet and engaged with the member of insulating material toswing the arms.

4. In an electro-magnet device for use with alternating currents, thecombination with a coil, of an armature ing a fixed member and a plungermember movable toward and from the fixed member, one of said memberscomprising sections of magnetic material, and a section of nonmagneticmaterial interposed between the sections of magnetic material and anactuating device operated by the plunger and securing the sectionstogether.

5. In an 'electro-magnetic device for use with alternating currents, thecombination with a coil, of an armature therein comprising a fixedmember of magnetic material and a plunger member movable toward and fromthe fixed member, said plunger member comprising sections terial, and asection of non-magnetic ma terial interposed between the sections ofmagnetic material, one of the sections of magnetic material operatingadjacent to and being attracted by the fixed member and" being soproportioned with respect thereto as to hold the plunger againstretrograde movement during the change in current and permit theretrograde movement of the plunger when the coil is deenergized.

6. In an electro-magnetic device for use with alternating currents, thecombination with a coil, of a fixed armature member therein, a stempassing through the fixed member, and a movable armature member thereincompris-' of magnetic ma comprising a section of magnetic material onthe stem cooperating with the fixed member, another section of magneticmaterial on the stem, and a section of non-magnetic material interposedbetween said sections of magnetic material, said stem constituting meansfor securing the sections together.

7 In an electro-magnetic device for use with alternating currents, thecombination with a coil, of a fixed armature member therein, a stempassing through the fixed member, and a movable armature member mountedon the stem, said movable member comprising a section of magneticmaterial cooperating with the fixed member, one of the adjacent races ofthe fixed member and section being recessed, another section of magneticmaterial having a hollow portion, and a section of non-magnetic materialinterposed between the sections of magnetic material.

8. In an electro-magnetic device for use with alternating currents, thecombination with a coil, of a fixed armature member and a plungerarmature member in the coil, one of said members comprising sections ofCopies of this patent may be obtained for magnetic material and asection of nonmagnetic material between said sections, one of thesections of magnetic material directly coacting with the other memberand being so proportioned thereto that it will retain its attractedrelation with respect to said other member during the change of current,but will be retracted from said position when the current ceases.

9. In an electromagnetic device for use with alternating currents, thecombination with a coil, of a fixed armature member, a

stem slidable through said fixed armature five cents each, by addressingthe Commissioner of Patents,

Washington, D. 0.

